The present invention is directed to a phased array operable at optical wavelengths.
Phased array antennas operating at microwave frequencies have long been used in applications such as radar, and provide the capability for electronically steering a beam from the array. However, the difficulties of implementing microwave phased arrays increase as the wavelength decreases, since the size of the components must decrease correspondingly. Phased arrays operable at optical wavelengths arrays could be used in display devices in place of cathode ray tube devices, and in applications such as optical memory readouts.
An information sheet apparently issued by the Defence Technology Enterprises, Ltd., Royal Signals and Radar Establishment, Worcestershire, UK, describes an integrated electro-optic device for steering light from a laser. The rear of the device is illuminated with light focussed to a spot. Divergence of light occurs to fill the array. Limitations of the device disclosed in this information sheet include the relative low efficiency, since much of the input light does not appear to find its way into an optical waveguide, lack of capability of providing a two dimensional array and apparent significant sidelobe energy.
Accordingly, it would represent an advantage in the art to provide an optical phased array which provides the capability of efficiently steering an output light beam in a desired direction.